Rumen and fecal microbial profiles in cattle fed high lignin diets using metagenome analysis.

Coconut coir (a lignin-rich, organic material) is widely used for its commercial and economic benefits. In this study, crossbred (exotic) and Kankrej (indigenous) breeds of cattle were fed diets containing 7 or 14% coconut coir. Metagenomic analyses (16S rRNA gene amplicon and shotgun sequencing) were used to characterize the microbial community in the rumen and fecal samples along with their functional capabilities. Both amplicon and shotgun analyses revealed the predominance of bacterial phyla, Bacteroidetes, Firmicutes, Actinobacteria and Fibrobacter in ruminal liquid, ruminal solid and fecal samples. 16S rRNA gene amplicon sequencing revealed a total of 18 different bacterial taxa were found to be enriched exclusively in the animals fed with 14% coir. The shotgun analysis revealed abundance of bacterial genera, Fibrobacter, Clostridium, Prevotella, Butyrivibrio, and Ruminococcus in both liquid and solid fractions of ruminal contents, while in the fecal sample, Bacteroides, Alistipes, Plaudibacter, Parabacteroides, Porphyromonas, and Victivallis and archaeal genus, Methanocorpusculum were abundant. The functional analysis based on dbCAN database suggested that among the Glycoside hydrolase family, genes that encode oligosaccharide degrading enzymes, GH3, GH13 (p-value < 0.05), and GH43 were abundant in the feces. In ruminal solid, cellulase encoding the GH5 family was abundant. Also, lignocellulosic binding modules encoded by the CBM family, including cellulose (CBM3) and hemicellulose binding modules (CBM32 and CBM67) were abundant. Thus, the study indicated the enrichment of lignocellulosic enzymes in ruminal contents in response to feeding the coconut coir, which could be mined for potential biofuel production and other biotechnological applications.

Structural insight into the fungal ß-glucosidases and their interactions with organics.

Fungal ß-glucosidases (BGLs) have unceasingly utilized for industrial applications and recently, they possess a crucial role in bioethanol production. To engineer the BGLs, understanding their structures, intermolecular interactions and molecular docking is requisite, which is carried out in this work based on the glycosyl hydrolase (GH) family. Among 12 BGLs, protein sequence, structure, and conserved sites of GH1 BGLs are evidently diverged to GH3 BGLs. Even biophysical and chemical features of GH1 BGLs are utterly varied from GH3 BGLs, wherein pI, instability index, aliphatic index, surface & buried area, thermostability and thermodynamics are included. On the contrary, aromatic, charged, polar, and hydrophobic residues are significantly higher in GH1 BGLs as compared to that of GH3 BGLs. Moreover, molecular docking of BGLs with 12 substrates and 5 inhibitors revealed that the GH3 BGLs efficiently bound with laminaribose, gentibiose, aryl- and cello-substrates than GH1 BGLs; however, GH3 BGLs are noticeably inhibited by glucose, glucono-δ-lactone, methanetriamine. So, structural insight of BGLs provides an explicit knowledge regarding the catalytic residues, biophysical chemistry and notable binding ligands, which are most important factors for enzyme engineering.

Microbiota composition, gene pool and its expression in Gir cattle (Bos indicus) rumen under different forage diets using metagenomic and metatranscriptomic approaches.

Zebu (Bos indicus) is a domestic cattle species originating from the Indian subcontinent and now widely domesticated on several continents. In this study, we were particularly interested in understanding the functionally active rumen microbiota of an important Zebu breed, the Gir, under different dietary regimes. Metagenomic and metatranscriptomic data were compared at various taxonomic levels to elucidate the differential microbial population and its functional dynamics in Gir cattle rumen under different roughage dietary regimes. Different proportions of roughage rather than the type of roughage (dry or green) modulated microbiome composition and the expression of its gene pool. Fibre degrading bacteria (i.e. Clostridium, Ruminococcus, Eubacterium, Butyrivibrio, Bacillus and Roseburia) were higher in the solid fraction of rumen (P<0.01) compared to the liquid fraction, whereas bacteria considered to be utilizers of the degraded product (i.e. Prevotella, Bacteroides, Parabacteroides, Paludibacter and Victivallis) were dominant in the liquid fraction (P<0.05). Likewise, expression of fibre degrading enzymes and related carbohydrate binding modules (CBMs) occurred in the solid fraction. When metagenomic and metatranscriptomic data were compared, it was found that some genera and species were transcriptionally more active, although they were in low abundance, making an important contribution to fibre degradation and its further metabolism in the rumen. This study also identified some of the transcriptionally active genera, such as Caldicellulosiruptor and Paludibacter, whose potential has been less-explored in rumen. Overall, the comparison of metagenomic shotgun and metatranscriptomic sequencing appeared to be a much richer source of information compared to conventional metagenomic analysis.

Culture independent assessment of human milk microbial community in lactational mastitis.

Breastfeeding undoubtedly provides important benefits to the mother-infant dyad and should be encouraged. Mastitis, one of the common but major cause of premature weaning among lactating women, is an inflammation of connective tissue within the mammary gland. This study reports the influence of mastitis on human milk microbiota by utilizing 16 S rRNA gene sequencing approach. We sampled and sequenced microbiome from 50 human milk samples, including 16 subacute mastitis (SAM), 16 acute mastitis (AM) and 18 healthy-controls. Compared to controls, SAM and AM microbiota were quite distinct and drastically reduced. Genera including, Aeromonas, Staphylococcus, Ralstonia, Klebsiella, Serratia, Enterococcus and Pseudomonas were significantly enriched in SAM and AM samples, while Acinetobacter, Ruminococcus, Clostridium, Faecalibacterium and Eubacterium were consistently depleted. Further analysis of our samples revealed positive aerotolerant odds ratio, indicating dramatic depletion of obligate anaerobes and enrichment of aerotolerant bacteria during the course of mastitis. In addition, predicted functional metagenomics identified several gene pathways related to bacterial proliferation and colonization (e.g. two-component system, bacterial secretion system and motility proteins) in SAM and AM samples. In conclusion, our study confirmed previous hypothesis that mastitis women have lower microbial diversity, increased abundance of opportunistic pathogens and depletion of commensal obligate anaerobes.